Deadlines for investigation can only be given by a High Court or the Supreme Court, according to the agency.

The Central Bureau of Investigation (CBI) has refused to accept Karnataka government's request to complete the investigation into the death of IAS officer DK Ravi in three months, saying deadlines for investigation can only be given by a High Court or the Supreme Court.

Accordingly, the agency has returned the probe request, IBNLive reported, citing CBI sources.

The agency has communicated it to the Department of Personnel and Training and sought for a fresh notification sans the deadline.

The state government had handed over the case to the CBI on 23 March and two days later, set a three- month deadline to complete the investigation. Prior to that, the Karnataka CID was probing Ravi's death case.

The decision to hand over the case to the CBI was taken after massive protests by Ravi's family, opposition parties and the general public, saying the CID probe won't be impartial. While they suspected it to be murder, the CID said the evidence collected during the initial investigation suggest it was suicide.

A WhatsApp message sent by 36-year-old Ravi to his female batchmate Rohini Sindhuri a day before he died allegedly strengthened the CID's inference.

"My last wish is to see you and kiss you but that will not be satisfied. And hence I expect you to come as soon as you hear my demise and look at me if possible hug me, kiss me and pray to god," the message by Ravi read.

Ravi, who busted the sand mining scam in Kolar district of Karnataka and fought with land and sand mafia, was found hanging from a ceiling fan of a room at his apartment on 16 March. His death triggered protests across the state, mainly in Kolar and Bengaluru.